This invention relates to a wheeled transport vehicle. The invention has particular application to trailers and incorporates structure which provides for the selective lowering or raising of the trailer frame.
It is known to incorporate in a trailer mechanism that will allow for the selective elevation or lowering of the trailer frame.
U.S. Pat. No. 3,837,665, issued Sep. 24, 1974, discloses an elevatable trailer having a tongue adapted to be coupled to a towing vehicle. A frame is provided with a tongue guide in which the tongue is movable forwardly and backwardly. Bell crank arms carrying wheels are pivoted on the frame of the trailer and linkage pivots the bell crank arms and elevates the frame when the tongue is pulled forward. Latch means is provided for latching the tongue in forward position relative to the frame for maintaining the frame in elevated position relative to the ground and on the wheels carried by the bell crank arms.
U.S. Pat. No. 5,975,828 discloses a suspension system for wheeled vehicles which allows the body or frame of a vehicle, such as the trailer, to be lowered or tilted. The suspension system includes an off-set axle which, when rotated, adjusts the clearance beneath the wheeled vehicle so that the body or frame thereof can be lowered or tilted. The off-set axle includes a central portion which can be rotated by applying tension to a tensioning member attached thereto.
The following patents also illustrate apparatus having a degree of relevance to the present invention: U.S. Pat. No. DES. 149,806, issued Jun. 1, 1948, U.S. Pat. No. 4,077,643, issued Mar. 7, 1978, U.S. Pat. No. 3,701,445, issued Oct. 31, 1972, U.S. Pat. No. 3,185,330, issued May 25, 1965, U.S. Pat. No. 3,620,397, issued Nov. 16, 1971, U.S. Pat. No. 4,494,797, issued Jan. 22, 1985, U.S. Pat. No. 3,837,665, issued Sep. 24, 1974, and U.S. Pat. No. 5,975,828, issued Nov. 2, 1999.
As will be seen below, the wheeled vehicle disclosed and claimed herein incorporates a number of unique features which contribute to the utility of the wheel transport vehicle. More particularly, the wheel transport vehicle constructed in accordance with the teachings of the present invention is characterized by its stability, strength and ease of use as compared with prior art constructions.
The present invention relates to a wheeled transport vehicle which includes a frame having a first frame member and a second frame member. The second frame member is slidably movable relative to the first frame member between an extended position and a retracted position.
A tongue projecting from and connected to the second frame member is operable to move the second frame member between the extended position and the retracted position when the tongue moves relative to the first frame member.
The transport vehicle also includes wheel mounting members pivotally connected to the first frame member and wheels rotatably disposed on the wheel mounting members.
A mechanical linkage interconnects the wheel mounting members and the second frame member and is responsive to movement of the second frame member from the extended position to the retracted position to pivotally move the wheel mounting members and move the wheels upwardly relative to the first frame member to lower the frame. The mechanical linkage is further responsive to movement of the second frame member from its retracted position to its extended position to move the wheels downwardly relative to the first frame member to raise the frame.
Other features, advantages and objects of the present invention will become apparent with reference to the following description and accompanying drawings.